Transformers having closed ferrite magnetic circuits

Abstract

A transformer, comprising: a closed ferrite magnetic circuit having an air gap; a rigid component filling a portion of the air gap; and, a flexible material filling the remainder of the air gap to substantially absorb vibrations of the ferrite. In the case of air gaps greater than approximately 1 mm, the flexible material fills approximately 1 mm of the air gap and the rigid component fills the remainder of the air gap. The rigid component may be of non magnetic, synthetic resin material. The flexible material may be a one component mastic, for example polysulfur, polysulfate polysulphide or polyurethane. The flexible material may also be a silicone type mastic, for example a neutral silicone.

What is claimed is:  
     
       1. A transformer comprising a closed ferrite magnetic circuit formed of a first half circuit and a second half circuit, the first half circuit and the second half circuit having respectively a first leg and a second leg for forming an air gap between said first leg and said second leg, a rigid component formed of a non-magnetic material being mechanically immobilized with respect to said first leg, said rigid component filling a portion of said air gap, and a flexible vibration absorbing material filling a remainder of said air gap and forming a continuous layer covering the end surface of the second leg. 
     
     
       2. A transformer according to claim  1 , wherein said air gap is more than one millimeter long. 
     
     
       3. A transformer according to claim  1 , wherein said transformer is usable in a switched mode power supply. 
     
     
       4. A transformer comprising a closed ferrite magnetic circuit formed of a first half circuit and a second half circuit, the first half circuit and the second half circuit having respectively a first leg and a second leg for forming an air gap between said first leg and said second leg, a rigid component formed of a non-magnetic material being mechanically immobilized with respect to said first leg, said rigid component filling a portion of said air gap, a flexible vibration absorbing material filling a remainder of said air gap and forming a continuous layer covering the end surface of the second leg, said remainder being less than {fraction (1/10)} of said gap long. 
     
     
       5. A transformer comprising a closed ferrite magnetic circuit formed of a first half circuit and a second half circuit, the first half circuit and the second half circuit having respectively a first leg and a second leg for forming an air gap between said first leg and said second leg, a rigid component formed of a non-magnetic material being mechanically immobilized with respect to said first leg, and a flexible vibration absorbing material filling the portion of the air gap between said second leg and the rigid component, and forming a continuous layer covering the end surface of the second leg.